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Increasing corrosion rate

I am currently researching the relationship between ambient temperature and corrosion rate on steel. These steel pieces are currently tested with a 5% NaCl @ 35degC salt spray (as per ASTM B117) for 1000 hours. I am charged with finding a way to reduce this testing time.

This topic has been widely discussed in a number of forums and websites, and everyone seems to agree that increasing the ambient temperature (until a certain point) will increase the corrosion rate. However, I have found no documents to support this claim, nor any definitive relationship between corrosion rate and temperature.

I am not a chemist or chemical engineer, merely an intern. Can anyone point me in the right direction? Thanks.

-Kevin

Reply to
dengetek
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If you don't believe, just measure the electric conductivity vs. temperature of your electrolyte.

Michael Dahms

Reply to
Michael Dahms

Are you really researching Temp vs corrosion rate, or are you charged with finding a way to reduce testing time on steel samples? The two things are different.

If the latter, then I suggest you take a look at ASTM G85, a much more rigorous test.

cheers

Reply to
Harry Andreas

The issue is that we were told a certain type of coating would last

1000 hours in a salt spray test with 5% salt @ 35degC, and we want to verify that this is true in a shorter time.

I made a mistake in my original post. The products are actually made of aluminum, not steel. And I also made the mistake of saying the corrosion rate of the steel (or aluminum) instead of the coating. Sorry for the mix up! I'm still learning. However, I think this would be inconsequential if I could determine a (such as the Arrhenius equation) corrosion rate vs. temperature relationship in any material undergoing a salt spray test.

I am not sure that the Arrhenius equation applies though, since this is a 'spray' test, not a 'bath' test. Is this correct? Wouldn't the corrosion rate also depend on the pressure of the spray?

Thanks.

-Kevin

Reply to
dengetek

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